Germ Cells of Leptinotarsa Signaticollis. 161 



At about the same time, Carnoy ('85) noted amitotic divisions in 

 the follicle cells of Gryllotalpa and a little later, Korschelt ('87) 

 made similar observations in the case of Hydrometra locustris. As 

 a result of studying the ovaries of Nepa cinerea and Locustra vir- 

 idissima, Preusse ('95) described amitosis not only of the nucleus, 

 but of the entire cell, and therefore claimed for the direct method of 

 cell division an active part in the multiplication of cells. De 

 Bruyne ('99), working in part with the same material, maintained 

 that in no case does the division extend to the body of the cell, and 

 that degeneration inevitably follows amitosis. Gross ('03) inter- 

 preted amitosis as he found it in eleven species of hemiptera in a 

 slightly different manner. Its occurrence among the nurse cells 

 is regarded as an indication of degeneration, but in the case of 

 the epithelial cells of the egg follicles it has a deeper significance, 

 for here it serves to enlarge the activity of the nucleus by increas- 

 ing the area of contact between it and the cytoplasm. 



The Ziegler-vom Rath theory (Ziegler '91, Ziegler and vom 

 Rath '91, vom Rath '95) briefly stated is as follows: Amitosis 

 appears in old and used-up tissue and consequently also in cells 

 which have a transient significance. It occurs principally in cells 

 which through very marked specialization take on the function 

 of intense secretion or assimilation. 



With the exception of Preusse, the unanimous opinion seems to 

 be that amitosis as it occurs in the insect ovary is confined to 

 division of the nucleus and is therefore not to be regarded as a 

 method of cell multiplication. Thus Kohler ('07) says; "Die 

 Kerntheilung der Nahrzellen und Follikelzellen die amitotisch 

 verlaufen, fiihren nie zu Zelltheilung. Diese Teilungen sind keine 

 Vermehrungsteilungen sondern Differenzierungsteilungen. Sie 

 bezwecken gar nicht eine Zellvermehrung und konnen deshalb 

 in keinen Weise gegen die Moglichkeit eine propagativen Bewei- 

 skraft besitzen." This conclusion may be accepted as the general 

 trend of opinion. Preusse's figures are far from convincing, and 

 his conclusions regarding this point have been severely criticized. 



In Leptinotarsa it has been shown that the large polynucleated 

 masses eventually break up into single cells, and if this is to be 

 looked upon as the last step of the amitotic process that started 



